Flower size preferences of the honeybee (Apis mellifera) foraging on Mimulus guttatus (Scrophulariaceae)

For pollinators to exert selection on floral traits, they must be able to detect and respond to differences in floral morphologies. I examined foraging preferences by the bee Apis mellifera (Apidae) visiting naturally occurring flowers of Mimulus guttatus (Scrophulariaceae). The results indicate that A. mellifera preferentially selects larger M. guttatus flowers in their foraging bouts. Since differences in flower size in M. guttatus have previously been shown to have a significant heritable component, I suggest that A. mellifera has the potential to be an important selective force in the floral morphology of M. guttatus.